1. Field of Disclosure
The present disclosure relates generally to cameras, and more specifically to an auto-exposure technique in a camera.
2. Related Art
A camera generally refers to a device, which is designed to capture an image of a scene. The image can be captured in digital form or analog form. To capture images in digital form, sensors may be arranged in the form of an array, with each sensor in the array forming a digital value representing a point (small portion) of the scene. On the other hand, in analog form, a light-sensitive medium is designed to respond to incident rays to capture the image. In general, the sensors and other media, which capture the images, are referred to as capturing medium.
The brightness of a captured image may depend, at least in part, on the amount/quantum of light from a scene that is incident on the capturing medium. Incidence of too little light may result in a poor quality dark image, while incidence of too much light may result in an overly ‘white’ image, again of poor quality. Accordingly, it is generally desirable to ensure that appropriate quantum of light is incident on the capturing medium.
The quantum of light incident is often controlled by causing a shutter assembly to be open for a duration (“open duration”) proportionate to the quantum of light deemed to be appropriate for the desired level of brightness. However, techniques such as varying the aperture of the shutter assembly, etc.( in general, configuring an exposure setting using corresponding exposure parameters) can also be employed in addition to or in combination with controlling open duration to obtain a desired level of brightness.
As the techniques of operating shutter assemblies generally ‘expose’ the capturing medium to a desired quantum of light, the techniques are referred to as exposure techniques. The open duration is referred to as exposure time.
Several cameras provide manual exposure techniques by which a user can configure the exposure parameters (open duration and/or aperture width in the above examples) to obtain a desired brightness level.
On the other hand, there has been a general recognized need for auto-exposure cameras. Auto-exposure generally refers to determining the appropriate exposure parameters (e.g., exposure time and aperture size in the examples above) to configure the shutter assembly, and performing the determined configuration by using appropriate computations and configurations within a camera.
In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the corresponding reference number.